ideas to make some POWER

[lecroy]

We still have no idea what sort of 650 we're discussing here, but what's all this crap about straight line speed? Any numpty can twist a throttle.

Why not embrace the far more subtle and refined art of turning your bike into a handling demon, and yourself into a highly skilled rider?

What's a numpty?

You bring up an interesting question. Why do people like to drag race? Your right, it's a very short, straight path with a couple of lights. The actual seat time to time invested is very poor compared to other racing. It's ignorant to think that all the skill that is required is to twist the throttle. You throw the whole E/T bracket class into it and it makes even less sense. You just need a little education is all.

I figure the original poster had mentioned drag and street. They asked about power, not handling. I guess the same would be true for handling (buy a newer bike) if this is your area of interest.

[brveagle]

I am speaking from experience here.. I have one of the, if not the fastest 2 valve 550's around and i at times regret hoping it out so much..

i'm still battling jetting issues due to custom squish areas and combustion chambers running HOT!

Don't do it

[tconroy]

We still have no idea what sort of 650 we're discussing here, but what's all this crap about straight line speed? Any numpty can twist a throttle.

Why not embrace the far more subtle and refined art of turning your bike into a handling demon, and yourself into a highly skilled rider?

First, install new fork springs, fine-tune the fork oil viscosity and set the right amount of sag using spacers (maybe $80 total and a couple of weekends of experimentation).

Next, bolt on some premium shocks ($200 and up for Progressive or Hagon, $350-$400 for Ikon, more if you want the full-zoot fully adjustable units.)

Somewhere in there, spoon on some premium modern sporty rubber -- Pirelli Sport Demons are the gold standard for GS handling. Maybe $220 a set, and you needed tires anyway, right? (The new Avon RoadRiders are also excellent, and a bit cheaper.)

You might also need to attend to the fork seals, swingarm bearings, and/or steering stem bearings along the way, none of which are very expensive.

Add in stainless steel brake lines and premium brake pads (anything but OEM).

Now here's the hard part: get the engine and carburetion back to bone stock (richen the idle mixture screws slightly), then LEAVE THE ENGINE ALONE. This means new o-rings for the carbs, seal the airbox, make sure the air filter is correct, and probably new engine/carb and carb/airbox intake boots. Set the float height very slightly rich, then fine-tune to achieve the smoothest possible transition from idle to 2,000 rpm.

You see, once the road begins to curve, Big Speed is not found at wide open throttle -- the secret is smoothness at low rpm, when you're just getting back into the throttle in a turn. The sooner and the smoother you can open the throttle, the faster you'll be. The amount of power matters only to goons who can only wobble through the turns then yank the wires open.

Of course, the final piece of the puzzle is you -- safely taking advantage of your bike's handling potential requires a high level of riding skill and committment to improving, maintaining and practicing that skill.

If you haven't already, take the MSF course, even if you've been riding for years. Listen, learn, and correct your bad habits to build the proper foundation.

Find some twisties and ride them as often as possible. Practice in parking lots. Program your brain with the angles when the peg drags on the right and the centerstand drags on the left. Ride with people who practice The Pace, not macho daredevils or pottering cruisers.
Article on riding The Pace: http://www.ridehsta.com/html/safety.htm

Attend a few GS rallies and tag along with the group up front. Don't try to keep up and ride over your head, but pay attention and learn firsthand what these old bikes are capable of in the right hands. Try to attend a track day or three if you can find one nearby that allows vintage bikes.

On a motorcycle, 99% of speed is the rider, and maybe 1% is the bike. Very few riders are willing to actively improve their skills, believing that they were born amazing and immortal. Take care of some of the basics on your bike and spend a few years improving your skills. You'll gain far more speed that way than by trying to turn a GS650 into a drag racer.

Plus, it's a lot more fun to watch the goobers on CBRs, GSXRs and Ninjas get smaller and disappear into your rear view mirrors when you're on an old, heavy, and "slow" bike.

bwringer is right because I have been there and done that! all progressive suspension new rubber and o-rings everywhere including cam chain tensioner.A stock 650 hauls pretty good and with the suspension upgrade and the engine tuned to perfection, not to mention new stator r/r and battery, you will have an excellent all around bike.The bikers skills are what make the bike. I can scrape the pegs or eat up the twisties and go on a long cruise down the highway at 70 to 90 mph for as long as it takes to get there and get lots of looks too!Im not the biggest guy in the world but I can throw this bike around pretty easy.

[ap72]

Yea, after finishing a long ride today I've decided that while it is a great bike to take out on the streets and especially on the back country roads, it doesn't have a good foundation at all to make some power. Usually I take cars in that situation and hotrod them just to be different but I realize bikes are a lot differenet in a lot of ways. I think I'll just save up and get a GSXR1000. I'll still do the engine rebuild on this one and make sure everything is in tip top shape, but hanging with the crotch rockets is a loosing proposition.

[bwringer]

What's a numpty?

You bring up an interesting question. Why do people like to drag race? Your right, it's a very short, straight path with a couple of lights. The actual seat time to time invested is very poor compared to other racing. It's ignorant to think that all the skill that is required is to twist the throttle. You throw the whole E/T bracket class into it and it makes even less sense. You just need a little education is all.

I figure the original poster had mentioned drag and street. They asked about power, not handling. I guess the same would be true for handling (buy a newer bike) if this is your area of interest.

The term "numpty" is evidence that I've been hanging around on British humor sites too much...

Anyway, a numpty is the idiot revving his engine over and over to make noise at the red lights, then taking off as fast as he can as soon as the light turns green... so he can sit at the next red light and repeat the performance ad nauseum. He will then foot-paddle slowly around any turn, including the right turn into the Dairy Queen or tavern, and then sit around with his fellow numptys and brag about all the horsepower they must be producing. Numptys are seen on all types of bikes, but are rarely seen with helmets or protective gear, and they are never found at an actual dragstrip or track.

I did not mean or imply any disrespect of actual drag racers. I prefer my racing and riding with lots of curves, but I do understand that drag racing is as subtle and advanced an art as roadracing, and also requires a very high level of skill to succeed.

It is true that any modern sportbike also has handling potential (and power and braking) far beyond anything imaginable in the '80s. However, it is extremely rare to encounter a rider capable of using even a fraction of the power, braking, and handling available. Just take a look at the squared-off chicken-stripped tires, poor maintenance, and wobbly cornering skills next time you see a gaggle of sportbikers.

When the road or track turns twisty, I guarantee that a rider with the skills to use his vintage bike anywhere near its potential will easily leave behind any numpty on any sportbike.

And, I repeat, squid hunting is a helluva lot more fun on an old, "slow" bike. Their little faces look so baffled, angry, and disappointed...

If you were on a modern bike, they would simply reason that you must have installed some sort of performance-enhancing modification they don't have, and all they need to do is figure out what it is and install one themselves to achieve the same performance.

But when someone on an old, heavy bike vanishes completely within two turns, they are left with the inescapable conclusion that they have witnessed a superior rider.

[bwringer]

... but hanging with the crotch rockets is a loosing proposition.

No, it's not a losing proposition. See above.

Get your bike in decent shape, and work on your skills. Unless you're descending into numptydom and simply "racing" stoplight to stoplight, you CAN and WILL keep up and leave the crotch rocketeers far behind riding your GS650.

On bikes, operator skill makes a much larger difference than it does in cars. On a road course or winding road, Jeff Gordon in a rusty '83 Corolla could never beat your average orthodontist in a new Corvette.

But in the world of bikes, the exact opposite is true. Loris Capirossi riding a 1963 Tohatsu Runpet would easily outpace the average unskilled sportbike rider on a new R1 (again, assuming curves are involved).

[Mysuzyq]

. Loris Capirossi riding a 1963 Tohatsu Runpet would easily outpace the average unskilled sportbike rider on a new R1 (again, assuming curves are involved).

I dig some of the vintage bikes, and immediately checked out my trusty motorcycle specs site http://www.motorcyclespecs.co.za/Index.htm to see what an R1 beating Runpet looks like, only to find no listing...probably super-rare eh?

Tony.

[bwringer]

I dig some of the vintage bikes, and immediately checked out my trusty motorcycle specs site http://www.motorcyclespecs.co.za/Index.htm to see what an R1 beating Runpet looks like, only to find no listing...probably super-rare eh?

Tony.

Here's a Tohatsu Runpet GP racer -- 11 stampeding horses! :mrgreen:

http://www.micapeak.com/HMarc/misc/tohatsu.html

Another fire-breathing Tohatsu Runpet:

http://www.lump-proof.com/CLASSIC/CRAFT/NC/runpet/index.html

I saw a reference to a Tohatsu Runpet in a magazine long ago, and I thought it was just something someone had made up to be a low-power laughingstock. But I did a little digging and found out that the Runpet was real. Still low power, but perhaps not a laughinstock.

[Mysuzyq]

Cool bike...thanks! 11+ bhp isn't too shabby from only 50 c.c if you think about it...a lot more h.p/c.c than an 1100E...or even a new Gixxer 1000!8-[
Okay...back to the GS650 power quest.

Tony.

[49er]

Now here's the hard part: get the engine and carburetion back to bone stock (richen the idle mixture screws slightly), then LEAVE THE ENGINE ALONE. This means new o-rings for the carbs, seal the airbox, make sure the air filter is correct, and probably new engine/carb and carb/airbox intake boots. Set the float height very slightly rich, then fine-tune to achieve the smoothest possible transition from idle to 2,000 rpm.

You see, once the road begins to curve, Big Speed is not found at wide open throttle -- the secret is smoothness at low rpm, when you're just getting back into the throttle in a turn. The sooner and the smoother you can open the throttle, the faster you'll be. The amount of power matters only to goons who can only wobble through the turns then yank the wires open.

Brian
I agree whole heartly with your
handling and braking improvement strategies and the huge benefits to be gained by this approach.
However, to claim that 99% of a riders speed can be attributed to his ability is a bit over the top.
I would put it more like this. If two riders had identically prepared machines (which is impossible to achieve anyway) and neither of them had ridden those bikes previously, the one who had honed his cornering and braking skills would always prevail over the other.
As for leaving the engine and carbs stock, I agree that in many cases this is the best idea.
However, tuners who have experimented with many performance parameters eventually reach a point where they go broke or finally work out what works and what don't. The ones that stick with it realise that they have to balance the mods to achieve the levels of reliablity, tractability and performance they desire.
My 850 is a case in point! The PO had left everthing stock except the Cycle Works 4-1 pipe and some minor jetting/needle position changes. I decided to increase the capacity and the CR and leave everthing else stock. The stock squish area and piston weights were retained to keep a balance to the mods. I slightly richened the pilot circuits and that was it. An electronic ignition was fitted to improve the whole power curve.
My point is this. I haven't dramatically changed the top or bottom end performance. I've just made the lower,middle and lower top end ranges that much stronger. These are the exact ares that I was seeking to enhance.
So, all street modifications should be kept well in balance. That's why we can still beat some of the pocket rockets. Their stock state of tune tends to be peaky. With their weight distribution well forward, they don't turn into corners as well balanced as ours, under hard braking.